@Kyudo,
thanks for replying. I can definitely see why you had issues even in normal instances, but panzerkin really takes a bit of proper gearing up before it can work. As a tank-wannabe it needs a fair bit of HP/armor and preferably crit immunity... which comes all in one package in PvP gear! (sucks that you have to PvP in order to PvE but can't have it all I guess). You should also look into the Balance WotLK talent tree, it will provide a major dps boost through moonkin aura + improved aura + earth and moon i think is what the talent is called.
IF you ever feel like giving moonkin another go(that's a big if, I know), try to get some S2 gear from honor, it really will make a big difference and for dps, swap from your current build 2pts from Brambles to Balance of Power and try to increase your crit%, your boomkin should definitely do more than 60% of the shammies dps with Wrath spam.

I know my experience with multiboxing ain't much, but i'm a Druid fanatic so I couldn't help myself including one in my multiboxing group and i'm definitely not regretting it so far!

@Drizzit, I hear you, that's why I decided to go for Moonkin instead of 4th shammy!